Have students research the size of a giant squid and make a measuring tape that shows the length of arms and tentacles, size of eyes, beak, siphon, etc. What are the other classes besides Cephalopoda in this phylum? How do they differ from the Cephalopods? What are the common characteristics of this group? Have students research the phylum Mollusca. Suggested Pre- or Post-Visit Activities and Resources Research has shown that these eggs are inoculated by a female squid with a host of bacteria that act as a microbial agent to prevent against disease and also seem to deter predators. Unlike octopi that guard their eggs after laying them, female squid die shortly after laying their eggs. Squids go through elaborate courtship displays with males passing sperm packets to the females, who then deposit hundreds of gelatinous eggs on the ocean, often in communal areas. Squids reproduce sexually with females producing eggs and males producing sperm. The third heart is the systemic heart which pumps the oxygenated blood to the rest of the body. Two of the hearts, the gill hearts, pump blood to the gills to obtain oxygen. Unlike most marine organisms, however, squids have three hearts. Like many marine organisms, squids have gills that they use to obtain essential oxygen from water. This shell provides the otherwise soft body of the squid with rigidity and helps maintain body shape. Some species of squid also possess hooks on their appendages thought to be used in defense and feeding.Īlthough squids lack an external shell, they do have remnants of an internal shell, called a pen because of its unique shape. These are equipped with suckers that are used in feeding. Squid are soft-bodied animals with eight arms and two longer tentacles. Squids also have an ink sac that can be used to produce a dark cloud in the water, thus confusing predators and allowing the squid to make their escape.
These chromatophores can provide camouflage for squid from predators and potential prey, but are also believed to be used for identification purposes and communication between squid.
SNAILS AND SQUIDS BELONG TO THE PHYLUM SKIN
Squid also possess chromatophores, specialized structures on their skin that contain pigment and allow them to change color rapidly. In fact, squids are the fastest swimmers among the invertebrates with some species reaching speeds of up to 25 mph.
Squid have a siphon that provides jet propulsion and fins to provide stability and direction when swimming. Squid are adept swimmers with several adaptations that allow them to move swiftly through the water.
There is also a large commercial fishery for squid as they are prized by humans as calamari and used by recreational fishermen as bait.īecause they are preyed upon by so many other organisms, squid have developed a number of specialized adaptations that help them avoid predators. As juveniles and adults, these creatures are preyed upon by numerous species of fish, birds, marine mammals and even other squids, and form a very important link in oceanic food webs. There are hundreds of different species that are distributed throughout the world’s seas, from the shallowest waters of our coastlines to the deepest portions of the ocean. Squids are the most highly developed and largest invertebrates on Earth.